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129 lines
3.4 KiB
C
129 lines
3.4 KiB
C
/* GStreamer
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* Copyright (C) 2003 Martin Soto <martinsoto@users.sourceforge.net>
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*
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* ac3_padder.h: Pad AC3 frames for use with an SPDIF interface.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifndef AC3_PADDER_INC
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#define AC3_PADDER_INC
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#include <glib.h>
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/* Size of an IEC958 padded AC3 frame. */
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#define AC3P_IEC_FRAME_SIZE 6144
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/* Size of the IEC958 header. */
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#define AC3P_IEC_HEADER_SIZE 8
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/* Size of the AC3 header. */
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#define AC3P_AC3_HEADER_SIZE 7
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/* An IEC958 padded AC3 frame. */
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typedef struct {
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/* IEC header. */
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guchar header[AC3P_IEC_HEADER_SIZE];
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/* Begin of AC3 header. */
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guchar sync_byte1;
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guchar sync_byte2;
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guchar crc1[2];
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guchar code;
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guchar bsidmod;
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guchar acmod;
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/* End of AC3 header. */
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unsigned char data[AC3P_IEC_FRAME_SIZE - AC3P_IEC_HEADER_SIZE
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- AC3P_AC3_HEADER_SIZE];
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} ac3p_iec958_burst_frame;
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/* Possible states for the reading automaton: */
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/* Searching for sync byte 1. */
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#define AC3P_STATE_SYNC1 1
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/* Searching for sync byte 2. */
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#define AC3P_STATE_SYNC2 2
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/* Reading AC3 header. */
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#define AC3P_STATE_HEADER 3
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/* Reading packet contents.*/
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#define AC3P_STATE_CONTENT 4
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/* Events generated by the parse function: */
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/* The parser needs new data to be pushed. */
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#define AC3P_EVENT_PUSH 1
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/* There is a new padded frame ready to read from the padder structure. */
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#define AC3P_EVENT_FRAME 2
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/* The internal state for the padder. */
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typedef struct {
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guint state; /* State of the reading automaton. */
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guchar *in_ptr; /* Input pointer, marking the current
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postion in the input buffer. */
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guint remaining; /* The number of bytes remaining in the current
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reading buffer. */
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guchar *out_ptr; /* Output pointer, marking the current
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position in the output frame. */
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guint bytes_to_copy;
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/* Number of bytes that still must be copied
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to the output frame *during this reading
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stage*. */
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guint ac3_frame_size;
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/* The size in bytes of the pure AC3 portion
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of the current frame. */
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ac3p_iec958_burst_frame frame;
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/* The current output frame. */
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} ac3_padder;
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extern void
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ac3p_init(ac3_padder *padder);
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extern void
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ac3p_push_data(ac3_padder *padder, guchar *data, guint size);
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extern int
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ac3p_parse(ac3_padder *padder);
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/*
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* ac3p_frame
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* @padder The padder structure.
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*
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* Returns a pointer to the padded frame contained in the padder.
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*/
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#define ac3p_frame(padder) ((guint *) &((padder)->frame))
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/*
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* ac3p_frame_size
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* @padder The padder structure.
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*
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* Returns the length in bytes of the last read raw AC3 frame.
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*/
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#define ac3p_frame_size(padder) ((padder)->ac3_frame_size)
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#endif
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